The present invention pertains generally to a system for indicating the locked-unlocked status of an exterior emergency or fire exit door.
Recognized building codes throughout the U.S., require that public buildings be provided with one or mor emergency exit doors which, by code, must remain unlocked when the building is accessible to the public. While such doors may include latches, they must be of the type released by one operation such as the actuation of a push bar. Such doors may be equipped with locks if the code requirement is satisfied that a visual indication is provided as to the locked-unlocked status of the door. Toward this end some building doors are equipped with mechanically actuated indicators which by nature are small and difficult to read from any distance. Such indicators are actuated by the bolt driving mechanism of the lock. Consideration has been given to enacting code requirements regarding electrical lock status indicators but heretofore such code requirements were not practical as suitable indicating systems and were not available to building owners.
A serious problem exists when existing switch arrangements are tried in door indicating systems. Erroneous indication of an emergency door status could result in loss of life and, at the least, a building code violation by the building owner.
The equipping of emergency doors with key operated locks is done to permit the building user to lock the door after public access has ended to permit the door from being used to provide entry and convenient egress to merchandise-laden burglars.
A switch sold by the Folger Adam Co., Model ASSW-104A termed a "keeper switch" provides a door frame mounted housing with a single switch lever protruding in the housing for actuation by a door bolt. Such a switch arrangement does not provide the necessary sensitivity to bolt movement.